3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE), that is, the improvement of an LTE Universal Mobile Telecommunications System (UMTS), has been introduced as 3GPP release 8. 3GPP LTE uses Orthogonal Frequency Division Multiple Access (OFDMA) in downlink and uses Single Carrier-Frequency Division Multiple Access (SC-FDMA) in uplink. 3GPP LTE adopts Multiple Input Multiple Output (MIMO) having a maximum of 4 antennas. Recently, 3GPP LTE-Advanced (LTE-A), that is, the evolution of 3GPP LTE, is being discussed.
A Minimization Drive Test (MDT) is that service providers perform a test using UE instead of a vehicle for coverage optimization. Coverage varies depending on the location of a BS, the deployment of peripheral buildings, and a user use environment. Accordingly, a service provider needs to periodically perform a driving test, and lots of costs and resources are consumed. An MDT is that a service provider measures coverage using UE.
An MDT can be divided into a logged MDT and an immediate MDT. In accordance with the logged MDT, UE performs MDT measurement and then transfers logged measurement to a network at a specific point of time. In accordance with the immediate MDT, UE performs MDT measurement and then transfers measurement to a network when a report condition is satisfied. In the logged MDT, MDT measurement is performed in an RRC idle mode, whereas in the immediate MDT, MDT measurement is performed in an RRC connected mode.
A service provider can write a coverage map, indicating whether or not service is possible over the entire area to which service is provided by a service provider and a distribution of QoS, by synthesizing pieces of MDT measurement received from several pieces of UE and use the written coverage map in network operations and optimization. For example, when a report on a coverage problem for a specific area is received from UE, a service provider can enlarge the coverage of a corresponding area cell by increasing the transmission power of a BS that provides service to the corresponding area.
Meanwhile, a recent UE device supports other wireless communication techniques, such as a WLAN (Wi-Fi), WiMAX, Zigbee, Bluetooth and/or a Global Navigation Satellite System (GNSS) as well as a wireless communication system, such as LTE. If such UE is In-Device Coexistence (IDC) UE, the transmission and reception of radio signals by another wireless communication can generate interference with the transmission and reception of LTE radio signals and vice versa. This may result in a problem in that quality of service provided to UE is deteriorated and efficiency of radio resources is also deteriorated.
Meanwhile, a network can make IDC interference avoided by controlling the operation of UE if it can obtain information about IDC interference within the UE. Accordingly, there is a need for a method for logging IDC interference information about IDC UE and reporting the logged IDC interference information to a network.